1. Field of the Invention
This invention relates to vehicles, specifically to improve passenger/payload positioning by using a center of gravity and mass shift control system.
2. Description of the Prior Art
Prior art has focused on the effect the regular and irregular surfaces of the ground has on the vehicle and thus to the passenger through the vehicle to passenger contact points. Prior art focuses on adjusting the vehicle system's alignment to the ground to reduce abrupt changes in position of the vehicle to passenger contact points. Prior art does not attempt to directly control the passenger center of gravity or mass except by indirect methods.
Prior art consists of automotive, motorcycle, bicycle and the like, designs that react after contacting an irregular surface in the vehicle path by releasing stored energy in suspension systems. Examples are the bicycle suspension systems disclosed in U.S. Pat. No. 4,881,750 to Hartmann, U.S. Pat. Nos. 5,445,401 and 5,509,677 to Bradbury, U.S. Pat. Nos. 5,456,480 and 5,580,075 to Turner, et al. The prior suspension systems during use are preset and not adjustable so these are passive or static suspension systems. The suspension may be too harsh or too soft for the surface conditions.
Prior art consists of automobile and bicycle suspension designs that react to the contact of an irregular surface and are controlled by measuring the rate of travel or the distance traveled by the device itself. Examples are the front bicycle suspension shocks that operate valves based on the speed of the shock piston shaft as disclosed in U.S. Pat. No. 6,026,939 to Girvin and Jones, as disclosed in U.S. Pat. No. 6,149,174 to Bohn, and automobile wheel suspension that is stiffened under increased loads from cornering as disclosed in U.S. Pat. No. 5,217,246 to Williams, et al. The above-cited systems are semi-active systems limited to the switching between two positions of hard and soft.
Prior art also includes designs that measure movement and timing of the suspension device after contacting an irregular surface then calculate the reaction with a preprogrammed controller that is limited in scope and without user input. One example of this system is disclosed in U.S. Pat. No. 5,911,768 to Sasaki. The above cited system is an active system and yet still limited by the preprogrammed controller.
Prior art also includes designs that measure movement of the C/G of the passenger/payload balanced above and rotated around a single axle restricting the C/G movement to a limited arc along one lateral plane as cited in U.S. Pat. No. 5,975,225 to Kamen, et al., as cited by the papers by Voss et al., “Dynamics and Nonlinear Adaptive Control of an Autonomous Unicycle—Theory and Experiment”, American Institute of Aeronautics and Astronautics, A90-26772 10-39, Washington, D.C. (1990), pp. 487-494 (Abstract only) and Koyanagi et al. “A Wheeled Inverse Pendulum Type Self-Contained Mobile Robot and its Two Dimensional Trajectory Control”, Proceeding of the Second International Symposium on Measurement and Control in Robotics, Japan (1992), pp. 891-898.
Prior art of the suspension systems disclosed earlier are based on the relationship of the contact points between the vehicle and the ground. The vehicle contact points to the passenger/payload are measured last or ignored all together. The range of motion of the C/G shifting in relationship to the constraints of the vehicle's passenger contact points has not been considered. Prior art control systems disclosed earlier focused on the measurement of the distance traveled or the rate of speed of the suspension devices themselves. The ride characteristics encountered by the center of gravity and mass shift of the passenger is two systems or linkages away from the attempted control points.
Prior art control systems disclosed earlier that appear to use center of gravity and mass shift measurements for control are actually measuring the pitch (lateral movement in one plane x) of a plate or body mounted above a single axle. The theoretical center of gravity is a gross approximation using this method. The inverse pendulum balancing method does work to place the center of gravity y-axis plane over the axle by moving the vehicle forward or back in a continuous recovery from a falling state. The C/G and mass elevation position in the Z-plane is disregarded and yet the height of the actual center of mass above the axle has a great influence on the effectiveness of the drive and balancing system. The single axle, single pendulum control method also has a weakness when encountering irregular surfaces that are soft or severely irregular. Power is applied through the wheels to continually adjust the location of the axle under the center of gravity. The reactive control has difficulty in keeping a constant power balance when a vehicle wheel has lost traction. An interactive center of gravity and mass shift control system that incorporated the measurement of the position of the center of gravity and mass in multiple planes would help prevent the over rotation of the center of gravity y plane at increased speeds.
Prior art active suspension systems based on ground induced input systems are not active in relationship to the actual rider position. All the prior active systems have focused on measuring the velocity or stroke (travel delta) of the suspension and then creating an output signal. The inputs have been velocity or travel measuring devices to a control circuit that outputs back to the original suspension devices. The advantage of the center of gravity and mass shift control system controlling a dynamically attached suspension system is the active relationship to the rider position.